This invention relates to exhaust gas silencing devices for use in the exhaust systems of motor vehicles having combustion engines. It concerns an acoustic component in which an outer metal shell is deformed into contact with a perforated gas flow tube to form a series of longitudinally separated chambers surrounding the tube and is a modification of the components described in U.S. Pat. Nos. 3,196,976 (issued July 27, 1965), 3,338,331 (issued Aug. 29, 1967), and 3,382,948 (issued May 14, 1968).